Transformer case



P 1965 e. 1.. GAGNON 3,208,020

TRANSFURMER CASE Filed Dec. 18, 1962 INVENTOR.

BY M, 2 0W W V 719,44

United States Patent O 3,208,020 TRANSFORMER CASE Glenn L. Gagno-n, Racine, Wis., assignor to Webster Electric Company, Racine, Wis., a corporation of Delaware Filed Dec. 18, 1962, Ser. No. 245,436 2 Claims. (Cl. 336-90) This invention relates generally to transformer cases and is particularly concerned with a new and improved ignition transformer casing which facilitates the making of electrical connections to a transformer located within the casing.

Ignition transformers are used to produce a spark for igniting oil burners or the like and, due to the large variety of furnace constructions upon which the transformers are to be installed, it is necessary to make electrical connections to the transformer from a variety of different areas within the furnace housing. For example, in one type of construction it becomes desirable to connect the wires supplying power for the transformer to a junction box located adjacent the transformer while in another type construction the primary lead wires of the transformer must be connected to the burner motor of the furnace to supply power. Prior practice in making connections of the latter type has been to use external leads leading out of the transformer casing to the area where the fan motor is located. These external connections are not only unsightly but, in addition, may interfere with the operation of the other components of the burner.

It is therefore, a principal object of the present invention to provide a new and improved casing for ignition transformers to make possible a number of different electrical connections without using unsightly external connectors.

A further object of the present invention is to provide a new and improved casing for ignition transformers which makes possible the use of a single transformer for a wide variety of burner applications.

Another object of the invention is to provide an ignition transformer casing so constructed and arranged that connections from the transformer to a power source located directly beneath the transformer mounting plate can be made internally through the transformer casing and through the mounting plate, thus avoiding the necessity for conductors extending externally of the transformer casing.

The foregoing and other objects are realized, in accordance with the present invention, by the provision of a transformer casing mounted upon a detachable base plate and housing a conventional power transformer. The casing is divided by a partition into two chambers, one for the transformer and the other forming a junction box area located adjacent the transformer chamber. The base plate is interchangeable and may be selected from any one of a number of available forms conventionally used for supporting different ignition transformers. The primary leads of the transformer extend into the junction box area through a passage in the partition. The transformer casing is provided with a plurality of knockouts adjacent the junction box area to permit direct connections from the power source to the transformer primary leads in installations where such direct connections are desirable. In addition, the transformer casing is provided with structure forming a raceway or channel communicating with an opening in the partition and extending from the junction box area to an area adjacent the base plate. The primary leads of the transformer pass from the junction box area through the latter channel and through suitable holes or knockouts in the mounting plate of connection to a power source located beneath the mounting plate. Since a connection to the transformer primary leads may be made either directly in the junction box area or from a power source located beneath the transformer mounting plate, the transformer casing of the present invention makes possible the use of a single transformer possessing a great degree of flexibility inasmuch as it may be used in a large number of different installations.

The invention, both as to its organization and manner of operation, together with further objects and advantages will best be understood by reference to the foil-owing detailed description taken in conjunction with the accompanying drawing wherein:

FIG. 1 is a longitudinal sectional view showing a transformer casing characterized by the features of the present invention;

FIG. 2 is a sectional view taken along a line substantially corresponding to the line 22 in FIG. 1 assuming, of course, that the latter shows the entire transformer construction;

FIG. 3 is a side view looking in the direction of the arrow pointed lines 33 in FIG. 1 with the junction box cover removed to show certain details of the construction within the junction box area of the ignition transformer casing; and

FIG. 4 is a sectional view taken along a line substantially corresponding to the line 4-4 in FIG. 3 assuming, of course, that the latter shows the entire con struction.

Referring now to the drawing, an ignition transformer casing generally indicated by the reference numeral 10 is there shown mounted upon an interchangeable base plate 11 which, in turn, is suitably secured to a support 12 forming part of the burner or furnace with which the transformer is to be used. The base plate 11 is interchangeable and may be selected from any number of different conventional forms. In the form illustrated in FIGS. 2 and 3 it is provided along one edge with a plurality of spaced slots 13 and along the opposite edge with a similar set of slots 14. A suitable mounting screw is inserted through each of the slots and into engagement with a tapped bore or opening in the support 12 in order to secure the base plate 11 to the support. The base plate is also provided with a plurality of spaced inwardly extending bosses 15, each having a central opening therein for receiving a mounting screw having a head portion seated within the countersunk area of the boss. One set of mounting screws and their cooperating bosses is used to secure the base plate 11 to the casing 10 while a second set is used to mount an ignition transformer 16. More specifically, the casing 10 has welded or otherwise secured to its interior a pair of L- shaped mounting legs 17, each having a leg portion extending inwardly from the casing wall to overlie a mounting boss 15. The latter leg portion is provided with an aperture for receiving one of the mounting screws 15a to secure the casing to the boss. The transformer 16 is mounted upon one or more brackets 22 which are in turn secured to the second set of mounting bosses 15 by means of screws 15a. The base plate 11 is also provided with a plurality of spaced apart dimples for aligning the transformer casing 10 on the base. A plurality of knockouts or openings 19 in the base plate 11 are provided to accommodate electrical conductors or wires 20 which are connected to a source of A.-C. power located beneath the base plate 11 or to the right of the support 12 as viewed in FIGS. 1 and 4. Each opening is aligned with an aperture 12a in the support 12 to permit the conductor to pass through the support for connection. A grommet 21 may be inserted into each of the openings 19 to prevent wear on the conductor extending therethrough.

The casing itself comprises a generally rectangularly shaped housing having an open end facing the base plate 11. The opposite or closed end is provided with a rela tively large access opening 23 which is normally closed by means of a detachable cover 24. The latter cover has a pair of inwardly bent ears 25 adapted to fit over the edge of the transformer casing adjacent one edge of the access opening 23. The opposite side edge of the cover has a small notch or slot 26 therein for accommodating a screw 27 which passes through the slot and into engagement with a tapped opening in the transformer casing, thereby detachably holding the cover 24 in position. An internal shelf or divider 28 is spot welded or otherwise secured to the interior of the casing 10 to divide the housing into a junction box chamber 29 and a transformer chamber 30. The chamber 30 houses the transformer 16 and is filled with a suitable insulating compound. The shelf 28 comprises a central raised dish like portion 31 and a flat peripheral ledge 32 having an inturned peripheral flange 33 thereon. The spot welding is made between the flange 33 and the interior of the casing 10. As is shown in FIG. 2, the shelf ledge 32 is provided with a pair of through openings 34 and 35 each accommodating one of the conductors 20 leading from the junction box chamber 29 to the input or primary winding terminals 38 and 39 of the transformer 16.

A direct electrical connection from the power source to the primary winding leads 20 may be made within the chamber 29 by inserting conductors leading from the source through any desired one of a plurality of openings in the casing 10. Each of these openings is normally closed by a conventional knockout in the junction box area of the casing. To permit access to the junction box chamber '29 from any desired direction in order to permit use of the transformer with many different types of burners or furnaces at least one knockout is provided in each side wall of the transformer casing 10. In the form shown in the drawing two of the side walls of the casing are each provided with a pair of knockouts 40 and 41 while each of the other two side walls is provided with a single knockout 42. Obviously, any one of these knockouts may be removed to make electrical connections from the source to the primary winding leads 20. A suitable grommet may be inserted into the knockout opening selected although such a grommet has not been shown in the drawing.

In certain installations it is desirable to connect the primary leads 20 to a source located beneath the mounting plate 11 or to the right of the support 12 as viewed in FIGS. 1 and 4. Prior to the present invention such a connection has been made by passing conductors out of the junction box chamber 29 through one of the knockout openings and by then running this conductor exteriorly of the casing to pass it through the support 12 for connection to the source. In accordance with an important feature of the present invention, however, the use of such external conductors is avoided by providing an internal channel or guideway 43 through which the primary conductors 20 may be passed from the junction box chamber. This channel is formed by an elongated curved guide member 44 having a pair of laterally depending legs 45 and 46 welded or otherwise secured to the interior of the transformer casing. The guide member 44 extends along one rounded corner of the transformer casing and communicates with a recessed or cut-away corner of the shelf ledge 32 to provide a through opening from the junction box chamber 29 to the transformer chamber 30. The member 44 terminates short of the bottom of the transformer casing to provide a space through which the conductors 20 may pass into the chamber 30 before being inserted through the aligned openings 19 and 12a. Thus, it will be observed that an electrical connection can be made from the primary winding terminals 38 and 39 of the transformer 16 to a source located beneath the mounting plate 11 without the use of conductors extending exteriorly of the casing 10. The connectors for making the latter connection extend from the terminals 38 and 39, through the openings 34 and 35 into the chamber 29, through the channel 43, through the chamber 30 and through the aligned openings 19 and 12a to the source.

In installations where the source is located to the left of the support 12 a direct connection is made from the source through one of the knockout openings in the transformer casing to the primary winding conductors 20. In installations of this type the conductors 20 may be severed so that the end portions thereof extending through the channel 43 and the openings 19 and 12a may be removed, if desired. The connections from the ends of the conductors 20 to the connectors from the source are then made within the junction box chamber 29 in any suitable manner, as, for example, by use of thimble type terminal members of conventional construction. The latter members have not been illustrated in the drawing in view of the fact that in the form of the invention thereshown the source is presumed to be located at the right of the support 12 or beneath the mounting base plate 11.

In view of the foregoing description it will be observed that all of the enumerated objects of the invention are accomplished by the structure described. The transformer casing of the present invention is extremely flexible and can be used in a wide variety of different installations.

While a particular embodiment of the invention has been illustrated and described it will be recognized that many modifications will readily occur to those skilled in this art and it is therefore contemplated by the appended claims to cover any such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is new and desired to be secured by Letters Patent of the United States is:

1. In combination, a transformer casing comprising an integrally formed generally rectangular shaped case having sidewalls joined with an end wall and an open end opposite said end wall, said end wall having an access opening defined therein, a detachable cover secured to said end wall for normally closing said access opening, a mounting plate detachably secured to said case covering said open end, opening defining means in said mounting plate, a shelf within said case joined at its periphery to at least one of said sidewalls and including a portion extending parallel to said mounting plate and end wall dividing said case into a junction box chamber adjacent said end wall accessible through said access opening when said cover is opened and a transformer chamber adjacent said mounting plate, a transformer mounted in said transformer chamber, a pair of transformer leads, first passage means defined in said shelf for accommodating passage of said leads extending from said transformer chamber to said junction box chamber and second passage means including aperture defining means in said shelf communicating with lead guide means within said case for accommodating passage of said leads extending from said junction box chamber into said transformer chamber before passage through said opening defining means in said mounting plate.

2. In combination, a transformer casing comprising an integrally formed case having sidewalls joined with an end wall and an open end opposite said end wall, a mounting plate detachably secured to said case and covering said open end, opening defining means in said mounting plate, shelf means joined to said case and dividing it into a junction box chamber adjacent said end wall and a trans- References Cited by the Examiner UNITED STATES PATENTS 2,740,905 4/ 56 Henderson 174--52 2,779,496 1/57 Henderson 174-60 2,903,662 9/59 Harvey 174--52 FOREIGN PATENTS 581,225 8/58 Italy.

JOHN F. BURNS, Primary Examiner.

JOHN P. WILDMAN, Examiner. 

2. IN COMBINATION, A TRANSFORMER CASING COMPRISING AN INTEGRALLY FORMED CASE HAVING SIDEWALLS JOINED WITH AN END WALL AND AN OPEN END OPPOSITE SAID END WALL, A MOUNTING PLATE DETACHABLY SECURED TO SAID CASE AND COVERING SAID OPEN END, OPEN DEFINING MEANS IN SAID MOUNTING PLATE, SHELF MEANS JOINED TO SAID CASE AND DIVIDING IT INTO A JUNCTION BOX CHAMBER ADJACENT SAID END WALLS AND A TRANSFORMER CHAMBER ADJACENT SAID MOUNTING PLATE, A TRANSFORMER MOUNTED IN SAID TRANSFORMER CHAMBER, A PAIR OF TRANSFORMER LEADS, FIRST PASSAGE MEANS DEFINED IN SAID SHELF MEANS FOR ACCOMMODATING PASSAGE OF SAID LEADS EXTENDING FROM SAID TRANSFORMER INTO SAID JUNCTION BOX CHAMBER AND SECOND PASSAGE MEANS COMPRISING APERTURE DEFINING MEANS IN SAID SHELF MEANS IN COMMUNICATION WITH LEAD GUIDING MEANS WITHIN SAID CASE FOR ACCOMMODATING PASSAGE OF SAID LEADS EXTENDING FROM SAID JUNCTION BOX CHAMBER INTO SAID TRANSFORMER CHAMBER BEFORE PASSAGE THROUGH SAID OPENING DEFINING MEANS IN SAID MOUNTING PLATE. 